This invention relates to food technology and, more particularly, to seafood products.
Imitation seafood products, or seafood analogs, are a fast growing segment of the food product industry. Such products result from processes wherein less expensive or underutilized fish or seafood varieties are converted into products with the form and taste of more desirable seafood varieties.
The most prevalent examples of seafood analogs are those derived from surimi. Surimi is a form of minced fish flesh which has been processed to remove water soluble proteins. The minced flesh that remains is surimi. It is comprised of water insoluble proteins, largely in the form of short muscle fibers. When the surimi is ground or minced into a finely comminuted paste in the presence of salt, the surimi turns into a sticky paste having gel-forming characteristics, as the salt aids in extracting otherwise insoluble proteins from the muscle fibers. When subsequently heated, the proteins thus extracted into the paste will denature and form a gel. The final shape of the product is thus dictated by whatever mold or form it occupies at the point when the surimi paste is solidified.
Surimi-based pastes are often used in forming seafood analogs, because of this gel-forming capacity, which also means that it can be molded or formed into virtually any desired shape. The gelling property also allows the texture to be varied somewhat, through controlling parameters involving gel strength and viscosity. Thus, the naturally occurring forms and textures of many types of seafood products can be duplicated, particularly those of shell fish. Other additives in addition to salt can be incorporated into the paste, and these often include flavorings derived from or reminiscent of the seafood variety to be duplicated.
In this manner, underutilized marine fish are processed for the taste or flavor of, and then molded into the form of, more desirable seafood varieties, with the most frequently duplicated products being relatively expensive or rare shellfish varieties such as crab, shrimp or lobster. Recent advances have involved improvements in such aspects as the formulation of the surimi paste, or in ways to affect the gel forming step to impart specific properties to the final product.
More specifically, many recent advances address the problem of providing a more natural texture to the surimi-based product, such as those disclosed in U.S. Pat. Nos. 4,301,812, 4,579,741, 4,584,204 and 4,919,959. These patents all provide processes for imparting a texture to the solidified surimi paste itself that will more closely duplicate the texture of the marine product being imitated.
Other approaches for incorporating more of a natural texture to surimi-like products are disclosed in U.S. Pat. Nos. 3,863,017, 4,362,752, 4,588,601 and 4,888,181. In these patents, processes are disclosed wherein the surimi paste is blended with other materials which provide the texture. In each case the added texturizing material is a fibrous material, and these are added to provide the product with a texture reminiscent of natural muscle fiber. The disclosed processes result in final products approximating the textures of such seafood varieties as shrimp, prawn, crab and lobster. The texture is due to the particular kinds and amounts of fibers incorporated into the surimi paste matrix prior to solidifying, or gelling, the matrix.
Because these surimi pastes form gels upon heating, it is easy to mold the imitation product into a desired shape. Because it is a gel, the final product will naturally have a rubbery or chewy feel. This limits the usefulness of such processes for duplicating fish products and when not producing shellfish analogs. In U.S. Pat. No. 4,301,182, an elaborate process is disclosed which duplicates a fish product such as flaked tuna. Dark meat portions of whole fish are minced into a fish paste and then extruded into a hot water bath. Extrusion is through a restricted orifice approximately 1 inch wide and 1/8 to 1/16 inch thick. The product is then further processed and preferably recombined with tuna loin meat prior to packaging
Although the form and texture of shell fish can be duplicated with surimi pastes, the flakiness or forkability of fish steaks or fillets cannot be achieved with existing surimi processes. Cooked fish flesh has a desirable flaky character, such that the layers of muscle are easily pulled apart. Forkability is a term which describes the manner in which pieces of the flesh of cooked fish will easily pull apart with moderate pressure applied by a fork. It has heretofore been impossible to duplicate these characteristics in imitation seafood products so that close analogs of such seafood products as fish fillets or fish steaks could be produced.
Among the objects of this invention, then, is to provide a process for producing formed fish products in a variety of heretofore unavailable forms and shapes.
A more specific object is to provide fish products which duplicate the form and feel of true fish fillets and steaks.
Another object is to provide a method for using surimi-based paste to produce analog fish products which have the form and feel of true fish fillets and steaks.
A further object is to provide a product of integrated fish flesh which holds its shape without the addition of breading or other external binders.
A still further object is to provide a method for producing imitation fish products where the texture of the final product is improved by utilizing as a starting material pieces of whole fish which have been cut or chunked and where the final fish product is fish flesh based.
Another object is to provide a fully cooked formed fish product which is available to the consumer refrigerated and in a sterile package, and which can be quickly and easily warmed for eating.